Intensification of
bioethanol production by simultaneous
saccharification and fermentation (SSF) in the
oscillatory baffled reactor (OBR)

Bioethanol is a promising
alternative fuel produced mainly by the
biochemical conversion of biomasses. This can be
carried out efficiently and economically by
simultaneous saccharification and fermentation
(SSF), a process which integrates the enzymatic
saccharification of the cellulose to glucose
with the fermentative synthesis of ethanol.
However, the SSF unit operation still
contributes nearly 50% to the cost of ethanol
production. For cellulosic ethanol to be cost
competitive, there is the need to intensify the
production process in smaller, more efficient
and more economical bioreactors. The crux of my
project involves evaluating SSF in an
intensified form of plug flow reactor, called
Oscillatory Baffled Reactor (OBR).

The OBR is a
continuous tubular reactor fitted with
equally-spaced orifice plate baffles. An
oscillatory component, provided by moving
bellows or pistons, is superimposed on the net
flow through the reactor, generating short-lived
vortices due to the interaction of the
oscillating fluid with the baffles. This results
in uniform mixing in each of the inter-baffle
regions, with each behaving as a stirred tank
reactor (STR), producing a plug flow residence
time distribution (RTD), in which the mixing
effects are largely decoupled from the mean flow
(unlike conventional PFRs).

The OBR, not
only enhances mixing but also intensifies the
entire process leading to smaller footprints,
capital cost savings, improved safety and better
conversion.